File upload

Hello, I am having a problem uploading a file. I have used struts <html:file> in a jsp and could upload a file without any problem. But when I have a file opened, say for example, I want to upload a word document "myfile.doc" and when this file is open, I can't upload. But when I close this file, then I am able to upload. Can any one suggest how I can upload a file even when it is open. Thanks